Root/package/gpio-button-hotplug/src/gpio-button-hotplug.c

1/*
2 * GPIO Button Hotplug driver
3 *
4 * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
5 * Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
6 *
7 * Based on the diag.c - GPIO interface driver for Broadcom boards
8 * Copyright (C) 2006 Mike Baker <mbm@openwrt.org>,
9 * Copyright (C) 2006-2007 Felix Fietkau <nbd@openwrt.org>
10 * Copyright (C) 2008 Andy Boyett <agb@openwrt.org>
11 *
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU General Public License version 2 as published
14 * by the Free Software Foundation.
15 */
16
17#include <linux/module.h>
18#include <linux/version.h>
19#include <linux/kmod.h>
20
21#include <linux/workqueue.h>
22#include <linux/skbuff.h>
23#include <linux/netlink.h>
24#include <linux/kobject.h>
25#include <linux/input.h>
26#include <linux/platform_device.h>
27#include <linux/gpio.h>
28#include <linux/gpio_keys.h>
29
30#define DRV_NAME "gpio-keys-polled"
31
32#define BH_SKB_SIZE 2048
33
34#define PFX DRV_NAME ": "
35
36#undef BH_DEBUG
37
38#ifdef BH_DEBUG
39#define BH_DBG(fmt, args...) printk(KERN_DEBUG "%s: " fmt, DRV_NAME, ##args )
40#else
41#define BH_DBG(fmt, args...) do {} while (0)
42#endif
43
44#define BH_ERR(fmt, args...) printk(KERN_ERR "%s: " fmt, DRV_NAME, ##args )
45
46struct bh_priv {
47    unsigned long seen;
48};
49
50struct bh_event {
51    const char *name;
52    char *action;
53    unsigned long seen;
54
55    struct sk_buff *skb;
56    struct work_struct work;
57};
58
59struct bh_map {
60    unsigned int code;
61    const char *name;
62};
63
64struct gpio_keys_button_data {
65    struct delayed_work work;
66    struct bh_priv bh;
67    int last_state;
68    int count;
69    int threshold;
70    int can_sleep;
71};
72
73extern u64 uevent_next_seqnum(void);
74
75#define BH_MAP(_code, _name) \
76    { \
77        .code = (_code), \
78        .name = (_name), \
79    }
80
81static struct bh_map button_map[] = {
82    BH_MAP(BTN_0, "BTN_0"),
83    BH_MAP(BTN_1, "BTN_1"),
84    BH_MAP(BTN_2, "BTN_2"),
85    BH_MAP(BTN_3, "BTN_3"),
86    BH_MAP(BTN_4, "BTN_4"),
87    BH_MAP(BTN_5, "BTN_5"),
88    BH_MAP(BTN_6, "BTN_6"),
89    BH_MAP(BTN_7, "BTN_7"),
90    BH_MAP(BTN_8, "BTN_8"),
91    BH_MAP(BTN_9, "BTN_9"),
92    BH_MAP(KEY_RESTART, "reset"),
93#ifdef KEY_WPS_BUTTON
94    BH_MAP(KEY_WPS_BUTTON, "wps"),
95#endif /* KEY_WPS_BUTTON */
96};
97
98/* -------------------------------------------------------------------------*/
99
100static int bh_event_add_var(struct bh_event *event, int argv,
101        const char *format, ...)
102{
103    static char buf[128];
104    char *s;
105    va_list args;
106    int len;
107
108    if (argv)
109        return 0;
110
111    va_start(args, format);
112    len = vsnprintf(buf, sizeof(buf), format, args);
113    va_end(args);
114
115    if (len >= sizeof(buf)) {
116        BH_ERR("buffer size too small\n");
117        WARN_ON(1);
118        return -ENOMEM;
119    }
120
121    s = skb_put(event->skb, len + 1);
122    strcpy(s, buf);
123
124    BH_DBG("added variable '%s'\n", s);
125
126    return 0;
127}
128
129static int button_hotplug_fill_event(struct bh_event *event)
130{
131    int ret;
132
133    ret = bh_event_add_var(event, 0, "HOME=%s", "/");
134    if (ret)
135        return ret;
136
137    ret = bh_event_add_var(event, 0, "PATH=%s",
138                    "/sbin:/bin:/usr/sbin:/usr/bin");
139    if (ret)
140        return ret;
141
142    ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
143    if (ret)
144        return ret;
145
146    ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
147    if (ret)
148        return ret;
149
150    ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
151    if (ret)
152        return ret;
153
154    ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
155    if (ret)
156        return ret;
157
158    ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
159
160    return ret;
161}
162
163static void button_hotplug_work(struct work_struct *work)
164{
165    struct bh_event *event = container_of(work, struct bh_event, work);
166    int ret = 0;
167
168    event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
169    if (!event->skb)
170        goto out_free_event;
171
172    ret = bh_event_add_var(event, 0, "%s@", event->action);
173    if (ret)
174        goto out_free_skb;
175
176    ret = button_hotplug_fill_event(event);
177    if (ret)
178        goto out_free_skb;
179
180    NETLINK_CB(event->skb).dst_group = 1;
181    broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
182
183 out_free_skb:
184    if (ret) {
185        BH_ERR("work error %d\n", ret);
186        kfree_skb(event->skb);
187    }
188 out_free_event:
189    kfree(event);
190}
191
192static int button_hotplug_create_event(const char *name, unsigned long seen,
193        int pressed)
194{
195    struct bh_event *event;
196
197    BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
198        name, seen, pressed);
199
200    event = kzalloc(sizeof(*event), GFP_KERNEL);
201    if (!event)
202        return -ENOMEM;
203
204    event->name = name;
205    event->seen = seen;
206    event->action = pressed ? "pressed" : "released";
207
208    INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
209    schedule_work(&event->work);
210
211    return 0;
212}
213
214/* -------------------------------------------------------------------------*/
215
216#ifdef CONFIG_HOTPLUG
217static int button_get_index(unsigned int code)
218{
219    int i;
220
221    for (i = 0; i < ARRAY_SIZE(button_map); i++)
222        if (button_map[i].code == code)
223            return i;
224
225    return -1;
226}
227static void button_hotplug_event(struct gpio_keys_button_data *data,
228               unsigned int type, unsigned int code, int value)
229{
230    struct bh_priv *priv = &data->bh;
231    unsigned long seen = jiffies;
232    int btn;
233
234    BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
235
236    if (type != EV_KEY)
237        return;
238
239    btn = button_get_index(code);
240    if (btn < 0)
241        return;
242
243    button_hotplug_create_event(button_map[btn].name,
244            (seen - priv->seen) / HZ, value);
245    priv->seen = seen;
246}
247#else
248static void button_hotplug_event(struct gpio_keys_button_data *data,
249               unsigned int type, unsigned int code, int value)
250{
251}
252#endif /* CONFIG_HOTPLUG */
253
254struct gpio_keys_polled_dev {
255    struct delayed_work work;
256
257    struct device *dev;
258    struct gpio_keys_platform_data *pdata;
259    struct gpio_keys_button_data data[0];
260};
261
262static void gpio_keys_polled_check_state(struct gpio_keys_button *button,
263                     struct gpio_keys_button_data *bdata)
264{
265    int state;
266
267    if (bdata->can_sleep)
268        state = !!gpio_get_value_cansleep(button->gpio);
269    else
270        state = !!gpio_get_value(button->gpio);
271
272    state = !!(state ^ button->active_low);
273    if (state != bdata->last_state) {
274        unsigned int type = button->type ?: EV_KEY;
275
276        button_hotplug_event(bdata, type, button->code, state);
277        bdata->count = 0;
278        bdata->last_state = state;
279    }
280}
281
282static void gpio_keys_polled_queue_work(struct gpio_keys_polled_dev *bdev)
283{
284    struct gpio_keys_platform_data *pdata = bdev->pdata;
285    unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
286
287    if (delay >= HZ)
288        delay = round_jiffies_relative(delay);
289    schedule_delayed_work(&bdev->work, delay);
290}
291
292static void gpio_keys_polled_poll(struct work_struct *work)
293{
294    struct gpio_keys_polled_dev *bdev =
295        container_of(work, struct gpio_keys_polled_dev, work.work);
296    struct gpio_keys_platform_data *pdata = bdev->pdata;
297    int i;
298
299    for (i = 0; i < bdev->pdata->nbuttons; i++) {
300        struct gpio_keys_button_data *bdata = &bdev->data[i];
301
302        if (bdata->count < bdata->threshold)
303            bdata->count++;
304        else
305            gpio_keys_polled_check_state(&pdata->buttons[i], bdata);
306    }
307    gpio_keys_polled_queue_work(bdev);
308}
309
310static void __devinit gpio_keys_polled_open(struct gpio_keys_polled_dev *bdev)
311{
312    struct gpio_keys_platform_data *pdata = bdev->pdata;
313    int i;
314
315    if (pdata->enable)
316        pdata->enable(bdev->dev);
317
318    /* report initial state of the buttons */
319    for (i = 0; i < pdata->nbuttons; i++)
320        gpio_keys_polled_check_state(&pdata->buttons[i], &bdev->data[i]);
321
322    gpio_keys_polled_queue_work(bdev);
323}
324
325static void __devexit gpio_keys_polled_close(struct gpio_keys_polled_dev *bdev)
326{
327    struct gpio_keys_platform_data *pdata = bdev->pdata;
328
329    cancel_delayed_work_sync(&bdev->work);
330
331    if (pdata->disable)
332        pdata->disable(bdev->dev);
333}
334
335static int __devinit gpio_keys_polled_probe(struct platform_device *pdev)
336{
337    struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
338    struct device *dev = &pdev->dev;
339    struct gpio_keys_polled_dev *bdev;
340    int error;
341    int i;
342
343    if (!pdata || !pdata->poll_interval)
344        return -EINVAL;
345
346    bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
347               pdata->nbuttons * sizeof(struct gpio_keys_button_data),
348               GFP_KERNEL);
349    if (!bdev) {
350        dev_err(dev, "no memory for private data\n");
351        return -ENOMEM;
352    }
353
354    for (i = 0; i < pdata->nbuttons; i++) {
355        struct gpio_keys_button *button = &pdata->buttons[i];
356        struct gpio_keys_button_data *bdata = &bdev->data[i];
357        unsigned int gpio = button->gpio;
358
359        if (button->wakeup) {
360            dev_err(dev, DRV_NAME " does not support wakeup\n");
361            error = -EINVAL;
362            goto err_free_gpio;
363        }
364
365        error = gpio_request(gpio,
366                     button->desc ? button->desc : DRV_NAME);
367        if (error) {
368            dev_err(dev, "unable to claim gpio %u, err=%d\n",
369                gpio, error);
370            goto err_free_gpio;
371        }
372
373        error = gpio_direction_input(gpio);
374        if (error) {
375            dev_err(dev,
376                "unable to set direction on gpio %u, err=%d\n",
377                gpio, error);
378            goto err_free_gpio;
379        }
380
381        bdata->can_sleep = gpio_cansleep(gpio);
382        bdata->last_state = 0;
383        bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
384                        pdata->poll_interval);
385    }
386
387    bdev->dev = &pdev->dev;
388    bdev->pdata = pdata;
389    platform_set_drvdata(pdev, bdev);
390
391    INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
392
393    gpio_keys_polled_open(bdev);
394
395    return 0;
396
397err_free_gpio:
398    while (--i >= 0)
399        gpio_free(pdata->buttons[i].gpio);
400
401    kfree(bdev);
402    platform_set_drvdata(pdev, NULL);
403
404    return error;
405}
406
407static int __devexit gpio_keys_polled_remove(struct platform_device *pdev)
408{
409    struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
410    struct gpio_keys_platform_data *pdata = bdev->pdata;
411    int i = pdata->nbuttons;
412
413    gpio_keys_polled_close(bdev);
414
415    while (--i >= 0)
416        gpio_free(pdata->buttons[i].gpio);
417
418    kfree(bdev);
419    platform_set_drvdata(pdev, NULL);
420
421    return 0;
422}
423
424static struct platform_driver gpio_keys_polled_driver = {
425    .probe = gpio_keys_polled_probe,
426    .remove = __devexit_p(gpio_keys_polled_remove),
427    .driver = {
428        .name = DRV_NAME,
429        .owner = THIS_MODULE,
430    },
431};
432
433static int __init gpio_keys_polled_init(void)
434{
435    return platform_driver_register(&gpio_keys_polled_driver);
436}
437
438static void __exit gpio_keys_polled_exit(void)
439{
440    platform_driver_unregister(&gpio_keys_polled_driver);
441}
442
443module_init(gpio_keys_polled_init);
444module_exit(gpio_keys_polled_exit);
445
446MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
447MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
448MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
449MODULE_LICENSE("GPL v2");
450MODULE_ALIAS("platform:" DRV_NAME);
451

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